POS0928 THE IDENTIFICATION OF PENTRAXIN 3 AS BIOMARKER OF DISEASE ACTIVITY IN IDIOPATHIC INFLAMMATORY MYOPATHIES
Authors: M. Fornaro, G. Carabellese, F. Cacciapaglia, C. Scioscia, L. Coladonato, V. Venerito, R. Bizzoca, D. Natuzzi, N. Lacarpia, G. Lopalco, F. Iannone
Journal: Annals of the Rheumatic Diseases (2022)

Background Muscle involvement is only one feature of idiopathic inflammatory myopathies (IIM). Muscle enzymes do not always represent the best marker of disease activity and other inflammation markers such as ESR and CRP may be normal even with an active disease. Pentraxin-3 (PTX3) is an inflammatory marker produced in many inflammatory and non-inflammatory cells and serum level has been related to higher risk of major cardiovascular events and atherosclerosis 1 . PTX3 levels have been examined in various rheumatic and autoimmune diseases 2 , but data of PTX3 levels in patients affected with IIM have not been reported. Objectives The aim of the current study was to identify whether serum PTX3 level could be a marker of disease activity in patients affected with IIM. Methods Twenty patients affected with IIM (13 Dermatomyositis and 7 Polymyositis), 10 rheumatoid arthritis patients and 10 healthy controls (HC) aged, sex and BMI matched were evaluated. PTX3 levels was assessed using a commercially available enzyme-linked immunosorbent assay (Human Pentraxin3 ELISA Kit, Abcam) kit. Three different cardiovascular risk scores were used to estimate the 10-years CV risk. Carotid intima media thickness (cIMT) was measured with a My Lab XPro80 (Esaote SpA, Genova, Italy) using a linear array ultrasound probe small parts broadband transducer (5–15 MHz) both in right and left carotid. Myositis disease activity was evaluated by using myositis disease activity assessment visual analog scales (MYOACT) [19] established by the International Myositis Assessment and Clinical Studies (IMACS) group. Manual muscle test (MMT8) was used to assess muscle impairment. Exclusion criteria were a diagnosis of diabetes or a history of previous major CV events. Results Demographic and disease characteristics of our cohort are showed in Table 1. IIM patients showed higher levels of PTX3 compared to HCs (518±260 pg/ml vs 275±114 pg/ml, p&lt;0.05), while no difference was observed compared to RA patients (383±260 pg/ml). PTX3 levels do not correlate with lipid levels, QIMT and cardiovascular risk scores both in IIM, RA and HC. No correlation was found between DAS28-ESR and PTX3 levels in RA patients. Of note, a direct correlation was found between PTX3 levels and MYOACT-GLOBAL DISEASE ACTIVITY (r=0.675, p=0.002), PTX3 levels and MYOACT- GLOBAL-EXTRA-SKELETAL MUSCLE DISEASE ACTIVITY (r=0.542, p=0.013), while an inverse correlation was found between PTX3 levels and MMT8 (r=-0.510, p=0.02). Table 1. IIM 20pz (13 DM, 7 PM) RA 10pz Healthy Control 10pz Female, n. (%) 18 (90%) 9 (90%) 9 (90%) Age 55,3 (7,8) 58,3 (5,9) 54,6 (6,5) BMI 25,5 (4,1) 23,9 (3,1) 24,6 (3,5) Duration of disease, median (IQR) 7,3 (4 – 12,8) 13,5 (10,5 – 18,5)* Physician Global Assessment 2,1 (2,1) 2 (2,2) Patient Global Assessment 4 (3,6) 2,7 (2,3) Health Assessment Questionnaire 0,7 (0,8) 0,9 (0,9) Manual Muscle Testing 8 76,2 (6,6) DAS28 2,6 (1,1) Skin involvement, n. (%) 13 (65) Lung involvement, n. (%) 7 (35) Dysphagia, n. (%) 11 (55) Arthritis, n. (%) 4 (20) Malignancies, n. (%) 0 (0) 0 (0) 0 (0) Arterial hypertension, n. (%) 6 (30) 2 (20) 1 (10) Current steroid therapy 2,5 (0 – 5) 0 (0 – 3,8) Smoking, n. (%) 6 (30) 2 (20) 3 (30) Total cholesterol, mg/dl 203,3 (28,6) 215,0 (29,5) 216,2 (27,3) HDL cholesterol, mg/dl 62,7 (14,7) 62,6 (14,2) 65,1 (18,2) ESR, mm/h 16,7 (12,2) 19 (11,7) PCR, mg/l 2,9 (2,1) 4,1 (5) SCORE median (IQR) 0,5 (0 – 2) 1 (0 – 3) 1 (0,8 – 1,3) CUORE median (IQR) 1,9 (0,6 – 3,5) 1,6 (1 – 4) 1,7 (1,2 – 2,8) QRISK3 median (IQR) 4,7 (2,1 – 11,3) 7,5 (3,2 – 13,6) 4,2 (3,1 – 5,5) QIMT Max, median (IQR) 742,5 (636,8 – 804) 833 (685,3 – 961) * 756 (711 – 820) Mean QIMT, median (IQR) 679 (613,1 – 736,3) 764,3 (664,5 – 854,1) * 703,3 (697,3 – 742,8) Pentraxin 3, pg/ml 518 (260) 383 (146) 275 (114)* Data are expressed as “mean (SD)” where not otherwise specified. *p&lt;0.05, **p&lt;0.01, ***p&lt;0.001 vs IIM Conclusion In IIM patients, PTX3 levels are higher than HC and correlate with disease activity, both for muscular and extra-muscular manifestations, being a possible biomarkers of disease activity. References [1]Front Immunol. 2019; 10: 823 [2]Arch Med Sci. 2020; 16(1): 81–86 Disclosure of Interests None declared